Analysis of Slug Frequency Correlations for Two-Phase Gas-Liquid Horizontal Slug Flow

2014 ◽  
Author(s):  
Manoella M. Antunes ◽  
Cristiane Cozin ◽  
Fausto A. A. Barbuto ◽  
Rigoberto E. M. Morales ◽  
Hendy T. Rodrigues
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Transient Flow ◽  
Industrial Applications ◽  
Gas Production ◽  
Two Phase ◽  
Oil And Gas Production ◽  
One Dimensional ◽  
Flow Parameters ◽  
Two Fluid

Multiphase flows in pipelines show several flow patterns depending on the industrial applications where they appear. In oil and gas production, typical flow rates, geometries and the physical properties of the phases make slug flow to be the most common of all patterns. This kind of flow is characterized by an intermittent succession of an aerated liquid slug region and a long, turbulent gas bubble surrounded by a liquid film. Due to its complexity, slug flow modelling has been a challenge to many researchers over the last four decades. Presently, steady-state one-dimensional models based on the unit cell concept and more accurate physical representations based on either two-fluid or slug tracking models embedding transient flow capabilities are available. These models require closure relationships for predicting flow parameters. In the present work, a literature review on frequency correlations is presented. An analysis of the performance of those correlations with experimental data for horizontal slug flows was carried out and its results are presented.

On the Numerical Modeling of Slug and Intermittent Flows in Oil and Gas Production

2017 ◽  
Author(s):  
Angela O. Nieckele ◽  
João N. E. Carneiro
Keyword(s):  
Oil And Gas ◽  
Fluid Model ◽  
Dynamic Pressure ◽  
Time Discretization ◽  
Gas Production ◽  
Two Phase ◽  
Dynamic Simulations ◽  
Oil And Gas Production ◽  
Two Fluid Model ◽  
Two Fluid

Recent advances on the modeling of two-phase flows in pipes have shown that the accurate modeling of Two-Fluid equations allow the dynamic simulation of various regimes within a single numerical framework, diminishing the empiricism associated with the flow-pattern dependent closure relations. Such “Regime-Capturing” approaches have been traditionally called “Slug-Capturing”, as a reference to dynamic simulations of stratified-to-slug transition. In this paper, we will outline several examples of applications, ranging from horizontal stratified wavy, slug and annular flows, to vertical annular and intermittent flows. Vertical flow has been a bottleneck in Slug Capturing due to ill-posedness of the Two-Fluid Model. Ill-posedness of the model equations will be briefly addressed along with different regularization methods and stabilizing terms based on physical behavior, such as shape profile factors and dynamic pressure contributions. In order to numerically solve the governing system of equations, the finite volume method is employed with Upwind and second order TVD spatial discretization schemes, along with first order time discretization. Flow parameters such as temperature and pressure drop are determined as well as film thickness and wave characteristics of both annular and stratified flow, and slug velocity, length and frequency in slugging cases. Comparison with experimental data for annular, slug and stratified flows, with different fluids and pipeline configurations are presented, illustrating the good performance of the methodology.

Multiphase Transient Slugging Flow in Subsea Oil and Gas Production

2016 ◽  
Author(s):  
Zhenhua Zhang ◽  
Longbin Tao
Keyword(s):  
Data Analysis ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Slug Flow ◽  
Field Data ◽  
Oil And Gas ◽  
Gas Production ◽  
Worst Case ◽  
Oil And Gas Production ◽  
Significant Difference

Slug flow in horizontal pipelines and riser systems in deep sea has been proved as one of the challenging flow assurance issues. Large and fluctuating gas/liquid rates can severely reduce production and, in the worst case, shut down, depressurization or damage topside equipment, such as separator, vessels and compressors. Previous studies are primarily based on experimental investigations of fluid properties with air/water as working media in considerably scaled down model pipes, and the results cannot be simply extrapolated to full scale due to the significant difference in Reynolds number and other fluid conditions. In this paper, the focus is on utilizing practical shape of pipe, working conditions and fluid data for simulation and data analysis. The study aims to investigate the transient multiphase slug flow in subsea oil and gas production based on the field data, using numerical model developed by simulator OLGA and data analysis. As the first step, cases with field data have been modelled using OLGA and validated by comparing with the results obtained using PIPESYS in steady state analysis. Then, a numerical model to predict slugging flow characteristics under transient state in pipeline and riser system was set up using multiphase flow simulator OLGA. One of the highlights of the present study is the new transient model developed by OLGA with an added capacity of newly developed thermal model programmed with MATLAB in order to represent the large variable temperature distribution of the riser in deep water condition. The slug characteristics in pipelines and temperature distribution of riser are analyzed under the different temperature gradients along the water depth. Finally, the depressurization during a shut-down and then restart procedure considering hydrate formation checking is simulated. Furthermore, slug length, pressure drop and liquid hold up in the riser are predicted under the realistic field development scenarios.

Gas-Newtonian and Gas-Non-Newtonian Slug Flow in Vertical Pipe, Part I: Gas Holdup Characteristics

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Subrata Kumar Majumder ◽  
Sandip Ghosh ◽  
Arun Kumar Mitra ◽  
Gautam Kundu
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Experimental Studies ◽  
Industrial Applications ◽  
Transportation Systems ◽  
Gas Holdup ◽  
Newtonian Liquid ◽  
Biochemical Engineering ◽  
Two Phase ◽  
Liquid Systems

Studies on two-phase gas-liquid co-current flow with non-Newtonian liquid system has attracted the attention of researchers over the years due to its wide-spread applications and importance in various different processes in chemical and biochemical industries, such as the process of two-phase in oil and gas wells, transportation systems of crude and refined products, and food processing in biochemical engineering and bio-reactors. This article examines the sole objective of experimental studies on gas holdup in Newtonian and non-Newtonian liquid slug flow within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m3/s and 1.6×10-4 to 6.7×10-4 m3/s, respectively. The present data was analyzed with different models. To predict gas holdup, correlations have been developed for individual system with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the gas holdup combing both the Newtonian and non-Newtonian liquid systems. The study of the gas holdup characteristics in gas-Newtonian and non-Newtonian liquid systems may give insight into a further understanding and modeling of this slug flow characteristics in industrial applications.

Gas Void Fraction Measurement in Two-Phase Gas/Liquid Slug Flow Using Acoustic Emission Technology

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
S. Al-lababidi ◽  
A. Addali ◽  
H. Yeung ◽  
D. Mba ◽  
F. Khan
Keyword(s):  
Acoustic Emission ◽  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Chemical Engineering ◽  
Oil And Gas ◽  
Gas Production ◽  
Engineering Industry ◽  
Two Phase ◽  
Gas Void Fraction

The gas-liquid two-phase slug flow regime phenomenon is commonly encountered in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Slug flow regime normally occurs for a range of pipe inclinations, and gas and liquid flowrates. A pipeline operating in the slug flow regime creates high fluctuations in gas and liquid flowrates at the outlet. Therefore, the monitoring of slugs and the measurement of their characteristics, such as the gas void fraction, are necessary to minimize the disruption of downstream process facilities. In this paper, a correlation between gas void fraction, absolute acoustic emission energy, and slug velocities in a two-phase air/water flow regime was developed using an acoustic emission technique. It is demonstrated that the gas void fraction can be determined by measurement of acoustic emission.

The Effect of Inclination on Flow Regime Boundaries and Slug Flow Characteristics

1989 ◽  
Vol 111 (3) ◽  
pp. 181-186 ◽  
Author(s):  
D. G. Wood
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Oil And Gas ◽  
Production Systems ◽  
Flow Characteristics ◽  
Gas Production ◽  
Research Centre ◽  
Test Rig ◽  
Oil And Gas Production ◽  
Capital Costs

Multiphase schemes for oil and gas production systems are becoming more common as the development of marginal fields necessitates a reduction in capital costs. Prediction of flow regime within these pipelines and the characteristics of the flow, especially within the slugging regime, is required in order to design the pipeline and the downstream separation and processing facilities. Test rig studies have been carried out at BP’s Sunbury Research Centre on the effect of small changes in pipeline inclination on both the flow regime and the characteristics of slug flow. Results from tests on a 2-in. rig are quoted.

Study of Slug Control Techniques in Pipeline Systems

2014 ◽  
Author(s):  
P. C. C. Monteiro ◽  
L. Loureiro Silva ◽  
J. L. A. Vidal ◽  
Theodoro A. Netto
Keyword(s):  
Control System ◽  
Flow Rate ◽  
Oil And Gas ◽  
Gas Production ◽  
Low Flow ◽  
Flow Loop ◽  
Two Phase ◽  
Automated Control ◽  
Oil And Gas Production ◽  
Automated Control System

Severe slugging may occur at low flow rate conditions when a downward inclined pipeline is followed by a vertical riser. This phenomenon is undesirable for offshore oil and gas production due to large pressure and flow rate fluctuations. It is of great technological relevance to develop reliable and economical means of severe slugging mitigation. This study aims to develop an automated control system to detect and mitigate the formation of severe slugging through a choke valve and a series of sensors. As a first step, an overall flow map is generated to indicate the region within which severe slugging may occur based on Boe’s criterion [1] and Taitel’s model [2, 3]. It was possible to obtain different flow patterns by controlling the rate of water and gas injection. The aim of this paper is, however, the formation of severe slugs and study of mitigation techniques. In the control part, we used a choke valve controlled by software which is in feedback with data from a system with pressure, temperature, flow, which are able to measure even small changes in the relevant parameters to the model. A two-phase flow loop was built for the study of severe slugging in pipeline-riser system with air and water as work fluids. The inner diameter of riser and flowline is 76.2 mm. The riser is 20 meters high and the flowline is 15 meters long and could be inclined upward or downward up to 8-degree. It has been shown by experiments how riser slugging can be controlled by automated control system.

Numerical simulation of two-phase flow regime in horizontal pipeline and its validation

2018 ◽  
Vol 28 (6) ◽  
pp. 1279-1314 ◽  
Author(s):  
Sam Ban ◽  
William Pao ◽  
Mohammad Shakir Nasif
Keyword(s):  
Flow Regime ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Production ◽  
Liquid Holdup ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Oil And Gas Production ◽  
Content Type ◽  
The Difference

Purpose The purpose of this paper is to investigate oil-gas slug formation in horizontal straight pipe and its associated pressure gradient, slug liquid holdup and slug frequency. Design/methodology/approach The abrupt change in gas/liquid velocities, which causes transition of flow patterns, was analyzed using incompressible volume of fluid method to capture the dynamic gas-liquid interface. The validity of present model and its methodology was validated using Baker’s flow regime chart for 3.15 inches diameter horizontal pipe and with existing experimental data to ensure its correctness. Findings The present paper proposes simplified correlations for liquid holdup and slug frequency by comparison with numerous existing models. The paper also identified correlations that can be used in operational oil and gas industry and several outlier models that may not be applicable. Research limitations/implications The correlation may be limited to the range of material properties used in this paper. Practical implications Numerically derived liquid holdup and holdup frequency agreed reasonably with the experimentally derived correlations. Social implications The models could be used to design pipeline and piping systems for oil and gas production. Originality/value The paper simulated all the seven flow regimes with superior results compared to existing methodology. New correlations derived numerically are compared to published experimental correlations to understand the difference between models.

scholarly journals An orthorhombic polymorph of 2-(1,3,5-dithiazinan-5-yl)ethanol or MEA-dithiazine

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Nate Schultheiss ◽  
Jeremy Holtsclaw ◽  
Matthias Zeller
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Oil And Gas ◽  
Polymorphic Form ◽  
Gas Production ◽  
Orthorhombic Space Group ◽  
Oil And Gas Production ◽  
Space Group ◽  
One Dimensional ◽  
Centrosymmetric Dimers

Substituted triazines are a class of compounds utilized for scavenging and sequestering hydrogen sulfide in oil and gas production operations. The reaction of one of these triazines under field conditions resulted in the formation of the title compound, 2-(1,3,5-dithiazinan-5-yl)ethanol, C5H11NOS2, or MEA-dithiazine. Polymorphic form I, in space group I41/a, was first reported in 2004 and its extended structure displays one-dimensional, helical strands connected through O—H...O hydrogen bonds. We describe here the form II polymorph of the title compound, which crystallizes in the orthorhombic space group Pbca as centrosymmetric dimers through pairwise O—H...N hydrogen bonds from the hydroxyl moiety to the nitrogen atom of an adjacent molecule.

Analysis of Numerical Simulation of Gas-Liquid Slug Flow Using Slug Tracking Model

2015 ◽  
Author(s):  
Stella C. P. Cavalli ◽  
Cristiane Cozin ◽  
Fausto A. A. Barbuto ◽  
Rigoberto E. M. Morales
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Initial Conditions ◽  
Computational Simulation ◽  
Flow Simulation ◽  
Gas Production ◽  
Liquid Slug ◽  
Two Phase ◽  
Tracking Model ◽  
Slug Flows

The distribution of the interfaces in gas-liquid two-phase flows in pipes can assume several shapes. Amongst those shapes, the slug flow pattern stands out as the most common one and occurs quite often in oil and gas production due to the flow rates and geometries used. This pattern is characterized by the succession of the so-called unit cells, that is, a flow structure composed of an aerated liquid slug and an elongated bubble surrounded by a liquid film. Due to its complexity, the study and understanding of this pattern’s behaviour becomes very important. The main methodologies used to describe slug flows are the steady-state one-dimensional models, based on the slug unit concept, and the transient approach, which takes the flow intermittence into account. The slug tracking model is one such transient approach, which considers slugs and elongated bubbles as separated bodies and analyzes the evolution along the flow and the interaction between those bodies. Whenever this model is numerically implemented, its initial conditions are important parameters that affect the results. The goal of this article is to study the influence of the initial conditions on slug flow simulation using the slug tracking model. A computer program written in Fortran95 using a slug tracking model to provide the characteristic parameters of slug flows such as the bubble and slug lengths and void fraction in the bubble region was built and used. The results were compared to experimental data and showed the important role the initial conditions play on the computational simulation of slug flow.

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